A top-mounted, high-sensitivity GPS/GLONASS receiver, TT 15 mini dog device uses 18 levels of continuous and momentary stimulation, plus audible tone and vibration activated from Alpha 100. Compatible with Astro 430 and 320 for tracking only. Rugged and water-resistant to 10 meters, this tracking and training dog device with collar is tough enough to run wherever your dog runs, up to 4 miles away.